Thomas w



(No Model.)

T. W. WHEATLEY.

GOAL SCREEN.

No. 302,806. Patented July 29, 1884.

UNirnn Smarts PATENT FFlQEt THOMAS \V. VVHEATLEY, OF \VILKES-BABRE,PENNSYLVANIA, ASSIGNOR TO JOSEPHINE G. SEITZINGER, OF SAME PLACE.

COAL=SCREEN.

SPECIFICATION forming part of Letters Patent No. 302,806, dated July 29,1884.

Application filed January 17, 1884.

T0 at whom it may concern.-

Beit known that I, THOMAS WTWnEA'rLnY, a citizen of the United States,and a resident olYVilkes-Barrc, Luzerne county, Pennsylvania, haveinvented certain Improvements in GoalScrcens, of which the'following isaspecication.

The object of my invention is to so construct a coal-screen that thebars of the same will be rigidly held in position in respect to eachother, thereby preventing; accidental change in the gage of the mesh inany part of the screen.

In the accompanying drawings, Figure 1 is aperspectir e View of part ofa coal-screen made in accordance with my invention; Fig. 2, a diagramillustrating the method of making the screen; and Figs. 3 and 4,enlarged sectional views of part of the screen, further illustrating themode of manufacture. v

For the purpose of separating and sizing coal, screens made of wovenwire are objectionable, because of the liability of the transverse barsto slip under the pressure exerted upon them, and thus change the gageof some of the meshes, this being the case even when the bars arecrimped, as is usual in making screens of large size. To overcome thisobjection, I make the screen of rolled bars fitted and securedtogetheiyone set of bars having notches, preferably dovetailed, for thereception of the other set.

In making the screen shown in Fig. 1, the notched cross-bar A issupported in an inverted position by the bed or lower die of a press, asshown in Fig. 2. The dovetailed 1ongitudinal bar B, also in an invertedposition, is applied thereto, and the upper die of the press is causedto descend, said upper die having lugs for acting on the bar B, on eachside (No model.)

of the bar A, as shown, so as to crimp said bar B and cause it to bindfirmly upon the barA, thus preventing the loosening of the cross-bar orthe release of the same from the notch,which effectually retains the baragainst longitudinal displacement, and thus insures the maintenance ofauniform gage of mesh throughout the screen. The bar A is then so actedupon by suitable dies as to conform to and firmly embrace the beveledbar B, as shown in Fig. 4, so as to prevent any vertical displacement ofthe, latter.

My improved screen is mainly intended for that class of separators inwhich the screen is made in segments, and applied to a cylindricalframe; but it may be used with other frames as well.

When it is desired to construct a screen in which the bars are readilydetachable, the crimping of the bars B may be dispensed with; but inmost cases this method of construction is preferable.

I claim as my invention' I 1. A coal-screen in which one set of dovetailed bars, B, are fitted to and secured within dovetailed notches inthe other set of bars, A, as set forth.

2. A coal-screen in which one set of bars. A, having dovetailed notches,are combined with a set of dovetailed bars, B, adapted to the notches,and crimped to confine the bars A, as set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THOMAS W. XVHEATLEY. lVitnesses:

WILLIAM L. STEWART, W. S. BENNETT.

